Color filters are essential components of solid-state image sensors. As a composition for a color filter, a negative-working curable composition including a pigment dispersion liquid, an alkali soluble resin, a photopolymerizable monomer, and a photopolymerization initiator has been proposed (for example, Japanese Patent Application Laid-Open (JP-A) No. 2-199403). In recent years, color filters for solid-state image sensors are required to provide higher image quality, and to form fine patterns while containing a high concentration of a colorant. While use of dyes in place of pigments as a colorant has been proposed (for example, JP-A No. 2006-317893), dyes have problems with color fastness. Therefore, at present, pigments are mainly used as the colorant.
It is known that a polyhalogenated zinc phthalocyanine having high chroma is used as a green colorant suitable for a solid-state image sensor (for example, JP-A Nos. 2007-284592 and 2007-320986). However, it has been found that when a green pattern is formed using the polyhalogenated zinc phthalocyanine, and red and blue patterns are further formed, needle crystals are generated in the green pattern.
In order to improve the contrast ratio of the color filter, a method for inhibiting the crystal growth caused by heating using a melamine compound has been proposed (for example, JP-A No. 2009-168955). However, the sufficient effect of preventing the formation of needle crystals cannot be obtained by using this method.